Safety appliance for push-button stations



April 14, 1931. H. E. EDHLUND SAFETY APPLIANCE FOR PUSH BUTTON STATIONS Filed Oct. 4, 1928 MEN ,WQBKING RE PArRfs W W f T m H Patented Apr. 14, 1931 PATENT OFFICE HENRY E. EDHLUNI), or NEWPORT, MINNESOTA SAFETY .AIPLIANCE FOR PlTSH-IBUTTON STATIONS Application filed October 4, 1928. I Serial No. 310,316.

My invention relates to a safety device for electrically operated machinery and the main object is to provide a simple, positive and inexpensive device particularly adaptable for so-called push button stations such as used in industrial plants, as hereinafter fully described and as illustrated in the accompanying drawing, in which,

Fig. 1 is atop .view of a push button station and my device applied thereto and in position shutting off current.

Fig. 2 is a front elevation of Fig. 1 with apad-lock added.

Fig. 3 is a right hand side elevation of 1'5 Fig. 2, showing also the switch actuating plate of my device in inoperative position in dotted lines.

Referring to the drawing by reference numerals, 5 designates the housin of. a well known so-called push button statlon suitably fixedon a wall 6 or other fixed element. Said station is provided with two exposed push buttons 7 and 8 designated respectively for start and stop. Pressing of button 7 2 will close circuit from a source'of electric current (not shown) to a motor (not shown) by any suitable circuit control means within.

housing 5, through a cable 9 and inversely pressing of button 8 will open the circuit and stop the'motor. Both buttons are normally pressed outwardly and positioned in a common plane.

As shown, the station box 5 is a vertically elongated closure with the buttons 78 .in

vertically spaced positions and protruding normally outwardl and forward from the face plate or cap 5 ofthe box. My device comprises mainly a plate 10 hinged as at 11 at its lower part to aibracket 12 suitabl fixed as at 13 to the lower part of box 5, an adapted to be swung on a vertical plane as from the hanging position shown dot-ted (Fig. 3) to the full line position shown in all the figures. 10L is a fixed or integral lug on plate 10, so positioned as to swing into contact with and press the stop button 8 when the plate is swung to vertical position over its hinge 11. Simultaneously the free upper end of the plate, being provided with an aperture 10A, slips over the horizontal arm 14A of an angle bracket 14 fixed as at 15 to the upper part of the cap 50. Said arm 141; has an aperture 16 into which an operator may engage the bolt 17B of a padlock 17 to thus hold the plate .locked in vertical position and with its lug 10L pressing button 8 and opening circuit within the station 5 and consequently, of course, caus ing cessation of any motor connected therewith. Thus it is impossible to start the motor and any machinery connectedwith it until the operator removes the padlock and permits plate 7 to be dropped down, when the stop button is released and the start button is accessible. It is well known in various industries that repair men and others are exposed to injuries by machinery being started in motion by others not knowing such parties are making repairs or adjustments and it is obvious that my device eliminates these con ditions. It would of course be compulsory for an operator to use my locking andcircuit opening means when a certainmachine is stopped and during the said inoperativeness of a machine no one but the said operator could again start operation.

Both faces of the plate may have certain predetermined warnings or Wording printed or affixed, such as the words. Danger and Men working on repairs. exposed when the device is in locked position'and on the other face of the plate may be placed suitable worda ing such as Safety first in bright, easily read colors.

I claim:

A safety control device for an electric switch for starting and stopping electrically operated apparatus and said switch having independent stop and start push-buttons;

said device comprising a plate hinged in proximit to the one of said buttons arranged to open t e electric circuit, a fixedclug on the plate positioned to engage and press said circuit opening button when the plate is swung 5 toward it upwardly, the free end part of said plate outwardly of said lug. arranged to be positioned close to the face of the other button of the switch when the first described button is pressed b the lug and means for I 1() locking sald plate ed in said circuit openin position.

11 testimony whereof I aflix my signature. HENRY E, EDHLUND. 

